Third wave has likely peaked in 4 of the 8 biggest cities

The third wave of the Covid-19 pandemic appears to have peaked in the four largest cities of the country, with the seven-day average of cases showing a clear decline in Mumbai, Delhi, Kolkata and Chennai.

However, the seven-day average, calculated till Friday, was still rising in the next four biggest cities of Bengaluru, Pune, Ahmedabad and Hyderabad. But here, too, Bengaluru and Ahmedabad had started showing signs of a slowdown, with daily cases dipping in the past two days, including Saturday, although the trend would have to sustain in the next few days for the seven-day average to start dropping.

The larger picture emerging from the Covid data of these eight cities is that the biggest urban centres were now contributing less and less to the country's daily infections. With the seven-day average of national cases still rising, the pandemic now appears to be spreading in the smaller cities and the countryside.

Going by the official figures, Bengaluru seems to have been the worst hit city during the current wave. It has recorded the highest peak and may probably end up logging the highest number of cumulative cases. The city has reported 3 lakh cases since December 16, only behind Delhi's total of nearly 3.4 lakh, with the gap narrowing with each day.

Mumbai was the first city where the pandemic peaked, with the seven-day average rising to 17,465 on January 12 before beginning to fall. Kolkata was next, reporting the lowest peak among the four largest metros of 7,069 on January 13. Delhi followed two days later with a high of 23,529 on January 15. Chennai posted a peak of 8,578 on January 19.

By contrast, Bengaluru's seven-day average stood at 24,091 on January 19 and was still rising, although the city reported a sharp dip on Saturday, with numbers falling to 17,266 from 29,000-odd on the day before.

In Mumbai and Delhi, the third-wave surge lasted around four weeks — from the time the seven-day average began to rise consistently till the peak. Kolkata saw the shortest surge of just 20 days while Chennai reported the longest one lasting 32 days.

Since the current wave is characterised by a vast number of unreported cases of asymptomatic patients and those with very mild symptoms, the official counts remain merely indicative of trends and are likely to be nowhere close to the actual numbers. Also, some cities could be testing more aggressively than others, leading to higher numbers there.

For the record, Hyderabad has the lowest official count of cases among the big eight in the third wave, having reported a little more than 25,000 cases so far since December 16. The city also saw its seven-day average of daily cases rise, then dip slightly before rising again.